Update quicksort.c

quicksort.c

@@ -1,68 +1,44 @@
 //Quick Sort
 
 #include<stdio.h>
-
-void swap(int *a,int *b)
+#include<stdlib.h>
+void partition(int*,int,int);
+void swap(int*,int*);
+int main()
 {
-    int t=*a;
-    *a=*b;
-    *b=t;
+ int *a,n;
+ printf("\nEnter size of the array");
+ scanf("%d",&n);
+ a=(int*)malloc(n*sizeof(int));
+ printf("\nEnter the array elements:");
+ for(int i=0;i<n;i++)
+  scanf("%d",a+i);
+ printf("Input array:\n");
+ for(int i=0;i<n;i++)
+  printf("%d ",*(a+i));
+ partition(a,0,n-1);
+ printf("\nResultant/Output array is:\n");
+ for(int i=0;i<n;i++)
+  printf("%d ",*(a+i));
+ return 0;
 }
 
-int partition(int arr[],int l,int r)
+void partition(int*a,int low,int high)
 {
-    int pi=arr[l];
-    int d=l+1;
-    int u=r;
-    while(1)
-    {
-        while(arr[d]<=pi && d<u)
-        {
-            d++;
-        }
-        while(arr[u]>pi)
-        {
-            u--;
-        }
-        if(d<u)
-        {
-            swap(&arr[d],&arr[u]);
-        }
-        else
-        {
-            swap(&arr[u],&arr[l]);
-            break;
-        }
-    }
-    return u;
+ int i=low-1;
+ for(int j=low;j<=high;j++)
+ {
+  if(*(a+j)<0)
+  {
+   i++;
+   swap(a+i,a+j);
+  }
+ }
 }
 
-void quicksort(int arr[],int l,int r)
+void swap(int *x,int *y)
 {
-    if(l<r)
-    {
-        int p=partition(arr,l,r);
-        quicksort(arr,l,p-1);
-        quicksort(arr,p+1,r);
-    }
+ int c=*x;
+ *x=*y;
+ *y=c;
 }
-
-int main()
-{
-    int n;
-    printf("\nEnter the No of Elements: ");
-    scanf("%d",&n);
-    int arr[n];
-    printf("\nEnter the Elements: ");
-    for(int i=0;i<n;i++)
-    {
-        scanf("%d",&arr[i]);
-    }
-    quicksort(arr,0,n-1);
-    printf("\nAfter Sorting the elements are: ");
-    for(int i=0;i<n;i++)
-    {
-        printf("%d ",arr[i]);
-    }
-    return 0;
-}